/*
 *  linux/kernel/printk.c
 *
 *  (C) 1991  Linus Torvalds
 */

/*
 * When in kernel-mode, we cannot use printf, as fs is liable to
 * point to 'interesting' things. Make a printf with fs-saving, and
 * all is well.
 */
#include <stdarg.h>
#include <stddef.h>
#include <linux/kernel.h>
#include <linux/sched.h>


static char buf[1024];

extern int vsprintf(char * buf, const char * fmt, va_list args);

int printk(const char *fmt, ...)
{
	va_list args;
	int i;

	va_start(args, fmt);
	i=vsprintf(buf,fmt,args);
	va_end(args);
	__asm__("push %%fs\n\t"
		"push %%ds\n\t"
		"pop %%fs\n\t"
		"pushl %0\n\t"
		"pushl $_buf\n\t"
		"pushl $0\n\t"
		"call _tty_write\n\t"
		"addl $8,%%esp\n\t"
		"popl %0\n\t"
		"pop %%fs"
		::"r" (i):"ax","cx","dx");
	return i;
}


static char logbuf[1024];
int fprintk(int fd,const char*fmt,...)
{
    va_list args;
    int count;
    va_start(args, fmt);
    count = vsprintf(logbuf, fmt, args); //将字符格式化写到缓冲区中 返回字节数
    va_end(args);
    struct file * file;
    struct m_inode * inode;

    if(3>fd)
    {
    //count=sys_write(3,logbuf,count);
        __asm__("push %%fs\n\t"
                "push %%ds\n\t"
                "pop %%fs\n\t"
                "pushl %0\n\t"
                "pushl $_logbuf\n\t"
                "pushl %1\n\t"
                "call _sys_write\n\t"
                "addl $8,%%esp\n\t"
                "popl %0\n\t"
                "pop %%fs" 
                ::"r"(count),"r"(fd)
                : "ax", "cx", "dx");
    }
    else
    {
        if (!(file = task[0]->filp[fd])) return 0;
        inode = file->f_inode;
        __asm__("push %%fs\n\t"
                "push %%ds\n\t"
                "pop %%fs\n\t"
                "pushl %0\n\t"
                "pushl $_logbuf\n\t"
                "pushl %1\n\t"
                "pushl %2\n\t"
                "call _file_write\n\t"
                "addl $12,%%esp\n\t"
                "popl %0\n\t"
                "pop %%fs" 
                ::"r"(count),"r"(file), "r"(inode)
                : "ax", "cx", "dx");
    }

    
    return count;
}